This invention relates to a simple, efficient and flexible peritoneal dialysis system utilizing a primary circuit of sterile dialysate solution and a secondary circuit of non-sterile dialysate solution.
Two conventional artificial approaches to treating blood poisoning as well as end stage renal disease and acute renal failure are hemodialysis and peritoneal dialysis. Both approaches serve to remove metabolic waste products (dialysis) and excess water (ultrafiltration) from the blood of a patient. In hemodialysis a portion of a patient's blood is circulated through a dialysis cell in which the patient's blood passes on one side of a semi-permeable membrane and a dialysate solution on the other side. The semi-permeable membrane passes the metabolic waste products and excess water from the patient's blood to the dialysate solution. Among the problems or disadvantages in hemodialysis are the need to chemically condition the blood against unwanted clotting and the need for removing blood from the body in an extracorporeal circuit to enable treating the blood. This latter need can give rise to blood component damage and blood pressure instability during the time the blood is out of the body.
In peritoneal dialysis, sterile dialysate solution is introduced into the peritoneal cavity of a patient, allowed to remain there for some predetermined period of time, and then removed (or at least a portion thereof) from the cavity. This alternate introduction and removal of dialysate solution is repeated for a sufficient length of time to remove metabolic waste products and excess water from the patient's blood circulating through the peritoneal membrane.
Although peritoneal dialysis simplifies or eliminates some of the problems presented with hemodialysis, a number of disadvantages still exist including the problem and danger of peritonitis, a lower efficacy than hemodialysis which therefore requires a longer treatment or process time with large volumes of solution, and the high cost of commercially prepared dialysate solution. This high cost arises from the need to use sterile dialysate solution to preclude peritonitis and the limited number of sources of commercially prepared dialysate solution.
An additional concern with currently available techniques for carrying out peritoneal dialysis is the need to maintain the proper blood chemistry balance for each patient treated where each patient may react differently to the dialysis treatment. That is, it is necessary to maintain a certain sodium electrolyte concentration which, during the dialysis process, tends to get out of balance because of the removal of water (ultrafiltration). When water is removed from the body by ultrafiltration, more water proportionally tends to be removed than does sodium, leaving an out of balance, higher-than-desired concentration of sodium in the water remaining in the body. As a consequence, as the dialysis process proceeds, it would be desirable to be able to carefully control the proportions of osmotic agent and sodium supplied back to the body via dialysate solution, and allow for adjustments, to ensure the maintenance of the proper concentration of sodium remaining in the body. Applicants are unaware of any systems presently available for doing this.
In U.S. Pat. No. 4,618,343, peritoneal dialysis apparatus is disclosed which utilizes a single bore catheter connected to a first circuit for delivering sterile dialysis solution from the first circuit to the peritoneal cavity of a patient and for removing dialysis solution from the cavity and returning it to the first circuit. The first circuit is coupled by way of a dialyzer to a second circuit which is operated in a single-pass mode to remove, through the dialyzer, metabolic waste products from the dialysis solution circulating in the first circuit. A so-called balancing chamber group is provided in the second circuit to control ultrafiltration. This balancing chamber group is connected to the inlet of the first dialyzer, and an outlet of the first dialyzer is connected back to the balancing chamber group.
Another two-circuit dialyzer system is disclosed in U.S. Pat. No. 4,190,047 in which a primary circuit is coupled by way of a catheter to the patient and by way of a dialyzer to a recirculating secondary circuit.